Looking for the set of slips on, but not loud (got some law restrictions) any ideas?

 

You can always drill a hole onto what you have to make them louder. Increase the hole until you get the right sound. If you don't like the sound you can get replacements slip-ons for a few dollars on Craigslist.

Most aftermarket pipes will be louder than stock, even with the smaller baffles so I am not sure if they will meet your criteria. Your best bet is to go to a bike rally and listen to other pipes and see if you find something that you like.

I am currently running Rush slip-ons with 1.75" baffles and they are loud but not too excessively loud.